Every car model that runs on gasoline today has similar construction scheme which includes various parts with different functions. In this scheme, the internal combustion engine is considered to be the heart of a vehicle because all other internal parts rely on its good condition. However, the combustion engine itself consists of parts that more or less contribute to its full operational state. One of those is the carburettor, a part without which a car will not be able to ignite and run.

Types of carburettors

Since its initial design, the carburettor has endured certain modifications and is now available in three basic types: one barrel, two barrel and four barrel version. Which type of carburettor will a particular car model use depends on the performance characteristics of its engine as high performance engines need larger amounts of fuel sucked into them?

What is a carburettor?

A carburettor is part of the car’s engine which blends air and fuel creating a spark that starts the internal combustion engine. Roughly explained, its basic structure includes a vacuum and two or several ports where air and fuel enter, creating a mixture that continues to the intake valves. Following this further, the carburettor operates on Bernoulli’s principle – when faster air moves inside the vacuum, the static pressure decreases and the dynamic pressure raises allowing faster flow of liquid fuel inside the vacuum. So, the carburettor does not affect the flow of fuel directly, but uses the flow of air to determine how much fuel will mix in the vacuum, consequently setting the acceleration speed. Sometimes, when the gas pedal is pressed and a car moves with idle or rapid acceleration, it’s a sign that there is a deficit of air flow needed to draw fuel. This is common problem associated with carburettor engines which is usually fixed by using other systems and parts of a vehicle, which shows that the carburettor relies on other parts of the car.

A well-functioning carburettor should be able to exactly measure the air flow in the engine and deliver the right amount of fuel to keep an optimal air/fuel mixture that results in better fuel economy of a car. That is why, if a car starts using more fuel than usual, car mechanics advice to check the carburettor’s condition. Not that the carburettor is the only source of the unexpected higher fuel economy, but in most cases, it turns out to be the main culprit.

However, few car owners have the knowledge and experience needed to detect carburettor malfunctioning or when it requires regular maintenance. In addition, we will describe some of the most common symptoms that indicate when something is wrong with the engine’s carburettor.

Darker smoke

Whether you’ve experienced it with your car or have seen it on the road, we are all familiar with a case where pure black smoke is coming out of the exhaust pipe. This defect can indicate number of things, but most often it refers to the malfunctioning of the carburettor and its inability to control the air/fuel ratio in the engine. Black smoke, along with poor engine performance, is a sure sign that you should check your carburettor for irregularities or indicate this on your next scheduled car service.

Problems starting your car

As we mentioned earlier, a carburettor in good condition is vital for proper igniting and starting a car. When you turn the key to start the car, the carburettor creates an optimal air/fuel flow inside the car engine which uses a spark from the engine spark plugs to ignite the car. So, if you have problems with the carburettor, it may not create a good air/fuel flow, or create no flow at all, thus restrain your car from igniting. On the other hand, most cars today have a carburettor which uses a choke mechanism that enhances the mixture to help start the car in these situations. Hence, worst case scenario would be a broken carburettor and a non-functioning choke mechanism.

Improper idle and acceleration speed

Another example of a defected carburettor is when you press the gas pedal and the engine reacts seconds later with high acceleration speed. This is a very familiar case with recent car models. What really happens is that the carburettor at some point skips air and consequently fuel flows in, creating an unexpected idle speed situation even when you hit the gas pedal hard. And a second later you instantly feel the awaited acceleration.

Therefore, in conclusion, the carburettor has two main roles in the performance of the engine, delivering gasoline and controlling speed. If any of these functions are not carried out perfectly, you should check the carburettor for possible faults. As we mentioned above, it can be difficult to trace this problem yourself, so if you notice any of the above indicators, please let your local car mechanic know about the symptoms you’ve noticed. I till help get a better diagnosis on the problem and save you some money if caught earlier.

About the Author

Chris Ireland has been a qualified mechanic for over 25 years and has operated a mechanical workshop in Brunswick for over 16 years. He always strives to achieve the highest quality of workmanship possible. He believes the key to a successful business is always treating the customer with the same respect that he would expect to receive if he was the customer.

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